3-甲基吡啶-N-氧化物深度氯化以提高产品收率

针对由3-甲基吡啶-N-氧化物与三氯氧磷生产2-氯-5-甲基吡啶过程存在的收率偏低问题,通过固体光气的深度氯化,使合成收率达到了76%,2-氯-5-甲基吡啶和2-氯-3-甲基吡啶合计总收率达95%,大幅度降低了生产成本。     

2,3-二甲基-4-硝基吡啶-N-氧化物的合成

以2,3-二甲基吡啶为原料,经氧化、硝化一锅法合成目的产物2,3-二甲基-4-硝基吡啶-N-氧化物,总收率70.3%。     

中间体3-氨基-2-氯-4-甲基吡啶的合成

介绍了中间体3-氨基-2-氯-4-甲基吡啶的9条合成工艺路线,从中选出较优的工艺路线进行合成研究,产品含量达到99.8%,收率达到65.4%.     

2-溴-6-三氟甲基吡啶合成的改进

介绍了标题化合物的合成路线,以2-氯-6-三氟甲基吡啶为原料,经过与水合肼、溴代反应得到目标产物,并经MS和1HNMR进行了结构表征。本合成路线操作简单,收率较高,适合工业化生产。反应总收率84.5%。     

2-氯-5-三氟甲基吡啶的合成

以氯化苄为原料,经过5步反应合成2-氯-5-三氟甲基吡啶.实验考察了反应条件对合成反应的影响,产品总收率达到37.4%.     

2-甲基吡啶和4-甲基吡啶合成工艺研究

以乙醛与氨为原料在常压下反应合成2-甲基吡啶和4-甲基吡啶．较佳反应条件为：反应温度为380℃,乙醛与氢物质的量比为3．0：2．0,收率可达50％以上．反应生成的混合2-MPD和4-MPD水溶液通过萃取、精馏可制得2-甲基吡啶(≥99．0％)和4-甲基毗啶(≥98．5％)成品。此工艺路线步骤简单、收率高、易于操作、适宜工业化。     

2,3-二甲基-4-硝基吡啶-N-氧化物的合成

以2，3-二甲基吡啶为原料，经氧化，硝化合成目的产物2，3-二甲基-4-硝基吡啶-N-氧化物，总收率70.3％。     

2,6-二甲基-4-羟甲基吡啶的合成

为了寻找一条合成2,6-二甲基-4-羟甲基吡啶的简单,经济的方法,本文以2,4,6-三甲基吡啶为原料,分别与间氯过氧苯甲酸、乙酸酐以及氢氧化钠经过3步反应,将原料从2,4,6-三甲基吡啶转变成相应的2,4,6-三甲基吡啶-N-氧化物、2,6-二甲基-4-羟甲基吡啶乙酸酯进而水解得到最终产物,总收率达51.2%。与文献合成方法相比,本法采用原料便宜,操作简单,收率高。     

3-甲基吡啶和4-甲基吡啶的分离技术进展

3-甲基吡啶与4-甲基吡啶是生产高附加值精细化工产品的重要有机原料,广泛应用于医药、农药、染料、香料、饲料添加剂、食品添加剂、橡胶助剂及合成材料等领域。笔者综述了3-甲基吡啶与4-甲基吡啶混合体系的各种分离方法,并对其应用前景进行了展望。     

2-氯甲基-4-乙氧基吡啶盐酸盐的合成

以2-甲基吡啶为起始原料,经N-氧化、硝化、乙氧基取代、酰化、水解、卤代等步骤,合成了2-氯甲基-4-乙氧基吡啶盐酸盐1,5步总收率为20%。     

纳米CaCO3粒子对不饱和聚酯树脂性能影响研究

本文使用纳米CaCO3粒子对196#不饱和聚酯树脂(UP)进行改性,考察不同质量分数的纳米CaCO3粒子对196#UP性能的影响。实验结果表明,树脂的凝胶时间、粘度随纳米CaCO3粒子用量的增加而增大。用量为1.0%时树脂有脆韧转变现象;用量为4%时拉伸强度和断裂延伸率分别提高约45%和67%,玻璃化温度Tg提高约30%,巴氏硬度提高34%。用KH-570偶联剂进行表面处理有利于纳米CaCO3粒子在UP中的分散。用扫描电子显微镜观测纳米CaCO3/UP拉伸断口形貌时发现,其微观形态在脆韧转变点附近有脆性断裂转为韧性断裂的形貌特征。     

The physical properties of sulfonated graphene/poly(vinyl alcohol) composites

Composites of poly(vinyl alcohol) (PVA) with sulfonated graphene (SG) show fibrillar, dendritic and rod like structures for SG1, SG3 and SG5 samples, respectively, where the number indicates weight percent of SG. Differential scanning calorimetry shows a new peak in addition to that of PVA arising from the supramolecular organization of the components in SG1 and SG3. Seventeen percent and 36% increases of PVA crystalline thickness and 77% and 79% increases in amorphous overlayer thickness for SG1 and SG3 over PVA are evident from small angle X-ray scattering results but SG5 does not show any change. Atomic force microscopy results of SG suggest aggregation at higher concentration and the composites exhibit composition dependent mechanical properties with the highest increase of stress (177%), strain at break (45%) and toughness (657%) in SG3 over PVA. Young’s modulus increases with increasing SG concentration with a maximum 180% increase in the SG5 sample. The storage modulus of SG3 shows the highest increase (1005%) over PVA. A 10 orders of magnitude increase of dc conductivity over PVA and a 10-fold increase in the dendritic SG3 to that of other composites are observed. SG1 is semiconducting, SG3 shows an electronic memory and SG5 exhibits a rectification property.     

Fe3O4磁性颗粒对聚砜超滤膜性能的影响

采用相转化法,制备不同纳米Fe3O4含量的PS-Fe3O4超滤膜,用扫描电镜观察Fe3O4颗粒的分布情况,并用磁强测量系统(MPMS)测量共混膜的磁性,以及通过对α-淀粉酶的超滤考察共混膜在磁场下截留率可以变化的特性.结果表明:PS-Fe3O4共混膜具有超顺磁性;膜的孔隙率、水通量、截留率随着Fe3O4含量的增高而增加;但当Fe3O4含量提高到25％时,易使膜产生结构缺陷,故确定较优Fe3O4添加量为20％.在磁场作用下,PS-Fe3O4超滤膜的截留率发生变化,随着Fe3O4含量的增高,磁变化效应增强.在0.4T的磁场下,共混膜中FeO4含量为5％,10％,15％,20％时,对α-淀粉酶的截留率分别比不在磁场中降低了3.5％,7.4％,12.3％,18.2％,表明Fe3O4磁性颗粒的添加不仅能改善膜的性能,而且能使膜具备截留率可调的特性.     

The effects of different cement dosages, slumps and pumice aggregate ratios on the compressive strength and densities of concrete

Compressive strengths of concretes made up of mixtures of pumice aggregate (PA) and normal aggregate were measured. To determine the effect of PA ratio, different cement dosage and slumps on the compressive strength of concrete, (1) 25%, 50%, 75% and 100% pumice ratios were used instead of normal aggregate by volume, (2) 200, 250, 350, 400 and 500 kg/m³ cement dosages were used and (3) 3±1, 5±1 and 7±1 cm slumps were also used in this study.The analysis of the test results leads to the conclusion that PA decreased the density of concretes up to 41.5% and reductions occurred due to the increase of the PA ratio in the mixes. With the increase of cement dosage in the mixes, both density and compressive strength of concretes increased up to 3.2% and 265%, respectively, when compared to the control sample that contain 200 kg/m³ cement dosage. The effect of the slump on the density and compressive strength was varied. Elasticity moduli were decreased with an increase of PA ratio and increased with an increase of cement dosage. Water absorption improved with an increase of cement content.     

工艺参数对铁尾矿制备泡沫玻璃性能的影响

以铁尾矿为主要原料、CaCO3和Na2CO3为发泡剂、Na3PO4×12H2O和硼砂(Na2B4O7×10H2O)为稳定剂,制备了性能良好的泡沫玻璃材料,并研究了工艺参数对制品性能的影响. 结果表明,CaCO3为主要发泡剂,Na2CO3含量对制品性能影响不大;Na3PO4×12H2O为主要稳定剂,Na2B4O7×10H2O含量不宜过多;发泡温度升高使制品孔径变大、容重和抗压强度降低;而烧结温度升高使制品的容重和抗压强度均先减小后增大. 制备泡沫玻璃适宜的工艺参数为(%, w)：基础玻璃84, CaCO3 3, Na2CO3 2, Na3PO4×12H2O 8, Na2B4O7×10H2O 3, 发泡温度900~950℃,烧结温度1100℃. 由此制得的泡沫玻璃材料容重约为2.05 g/cm3,抗压强度达62 MPa左右.     

Reply to Comment on “The Impact of Composite Effect on Dielectric Constant and Tunability in Ferroelectric‐Dielectric System”

In the comment on “The Impact of Composite Effect on Dielectric Constant and Tunability in Ferroelectric–Dielectric System”, Padurariu et al. proposed that a 2D system and a 3D system are not exactly similar: with the increase in dielectric content, the tunability of 2D system increases first and the tunability of 3D system decreases gradually. However, in my recent work, an abnormal increase in tunability was observed in the simulation result of 3D ferroelectric–dielectric model: with the increase in dielectric content from 0 to 60 vol%, the tunability increased from 22.8% to 31.4%.     

Long-chain acyl-CoA levels in liver from rats fed high-fat diets: Is it of significance for an increased peroxisomal β-oxidation?

The levels of long-chain acyl-CoA in the livers of rats given diets containing various amounts of dietary oils were investigated. Increasing the amount of soybean oil in the diet from 5% to 25% (w/w) led to a 40% increase in long-chain acyl-CoA. With partially hydrogenated marine oil, a sigmoidal doseresponse curve was obtained, giving a 60% increase when 20% or more of this oil was in the diet. All high-fat diets tested resulted in higher levels of long-chain acyl-CoA than the low-fat control containing soybean oil. The increase was most prominent with partially hydrogenated marine and rapeseed oils. With diets containing partially hydrogenated marine oil, the ratio of long-chain acyl-CoA to acid-soluble CoA was increased after 3 days, but decreased after 3 weeks, to a value similar to that observed in animals fed soybean oil because of an extensive increase in acid-soluble CoA. Increased levels of long-chain acyl-CoA were also observed after clofibrate was administered, but the increase was less prominent than observed with high-fat diets. When comparing the levels of long-chain acyl-CoA observed after 3 days on different diets with the peroxisomal β-oxidation activity previously determined after 3 weeks on the corresponding diets, a straight line was obtained. These results are discussed in relation to the possibility that long-chain acyl-CoA induces peroxisomal β-oxidation activity.     

低温烧结CuO-V_2O_5-Bi_2O_3掺杂Zn_3Nb_2O_8陶瓷的微波介电性能

研究了CuO–V2O5–Bi2O3作为烧结助剂对Zn3Nb2O8陶瓷的烧结特性、微观结构、相结构及微波介电性能的影响。CuO–V2O5–Bi2O3复合掺杂可以将Zn3Nb2O8陶瓷的烧结温度从1150℃降到900℃。在900℃烧结4h的Zn3Nb2O8–0.25%(质量分数,下同)CuO–1.5%V2O5–1.5%Bi2O3陶瓷的密度达到了理论密度的98.1%,相对介电常数为18.8,品质因数与谐振频率之积为39442GHz。该体系的介电性能和陶瓷的致密度与烧结助剂的含量及烧结温度密切相关,陶瓷的致密度和相对介电常数随CuO–V2O5–Bi2O3烧结助剂含量的增加而增加,同样陶瓷的致密度和相对介电常数也随烧结温度的升高而提高。     

A/O-MBR处理高浓度氨氮油页岩干馏废水

采用缺氧/好氧-膜生物反应器(A/O-MBR)工艺处理油页岩干馏废水,考察了启动期反应器中COD和NH4+-N的去除情况,探讨稳定期污泥混合液回流比、碳氮比和进水方式对COD、NH4+-N、TN去除效果的影响。结果表明,混合液回流比为300%~700%,TN去除率由87.67%提高至95.99%,但混合液回流比提高至900%时,其对废水处理效果影响不大。废水COD和TN的去除率随进水碳氮比的升高而提高,碳氮比由3提高至8,COD和TN的去除率分别由91.39%、82.81%提高至96.33%、92.21%。进水碳氮比为3,采用分段进水,废水TN去除率为90.05%,可提高废水处理效果。     

Infrared Transparent Germanate Glass-Ceramics

A new germanate glass-ceramic material in the BaO-Ga₂O₃-GeO₂ system is developed for infrared (IR) dome and window applications. This glass-ceramic material has a grain size of ∼0.2–0.5 μm and is transparent in the 3–5 μm IR region. Glass ceramization results in 40% improvement in hardness, 65% increase in elastic modulus, 116% increase in strength, and 134% increase in fracture toughness over the base glass.